The girl opens her eyes in a desolate world, and hears "your" voice from in front of the screen.

You can direct her actions, help her solve mysteries, evade dangers, and find a way to leave this place. Of course, you could also choose not to do so, or even worse, deliberately guide her to death... Just kidding, you surely wouldn't do that, right?

There is no role-playing

You are who you are, the one who guides Alice in front of the screen.
You can be honest, you can be deceitful, you can help, you can destroy.
But don't forget, you can't hide behind another identity.
She'll remember - remember everything you've done.